Microstructures and mechanical properties of (AlCoCrFeMn)_{100 − x}Cu_x high-entropy alloys

A series of (AlCoCrFeMn)_{100 −x}Cu_x high-entropy alloys (0, 4, 8, 12, 16 at.-%) were prepared by vacuum arc furnace melting and their phase composition, microstructure and mechanical properties were systematically investigated. The results show that Cu can induce phase transformation from the orthorhombic phase to the Laves phase in (AlCoCrFeMn)_{100 −x}Cu_x high-entropy alloys and the volume fractions of Laves phase increases from 0 to 70% with increasing Cu content. The compression fracture strain increases from 5 to 16% and the compression fracture strength also increases from 1380 to 2140 MPa with Cu content increases. The increased volume fraction of the Laves phase is the main factor for the ductility increases.